The invention particularly is an improved shutttering apparatus over the kind known from DT-GM No. 73 44 616, A German Patent Publication; there the shuttering walls are moved by means of a geared drive, the driving shaft of which extends parallel to the longitudinal direction of the precast concrete unit. However, in order to counteract the concrete pressure when casting precast concrete units and to secure the shuttering walls from sliding back, in the known shuttering there are necessary additional support devices which are fitted with threaded spindles. These have to be placed individually before each cast and have to be tightened by hand as well as be loosened and removed after each cast.
It has been found that particularly in very large and high shutterings, this kind of construction is quite satisfactory. The clearance of the sliding guide at the basic frame which is necessary for a sufficient easy mobility of the movable shuttering wall makes an exact adjustment of the shuttering wall distance in the upper range practically impossible, because when casting there are enormous forces affecting the shuttering walls and the mentioned clearance the more becomes effective inclining the shuttering wall against an exact vertical position, the higher shuttering walls being in comparison to their support basis. In addition comes the intricate handling of a spindle support devices which result in loss of time and high wage costs.